# iPeriodic for iPhone vs Formula Conversion

The clearest difference is update cadence: iPeriodic for iPhone at every 8 days against Formula Conversion's every 26 months. iPeriodic for iPhone also leads on iOS requirement (6.1 vs 14.1). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. iPeriodic for iPhone sells 1 one-off in-app purchase and Formula Conversion sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

iPeriodic for iPhone ships an update every 8 days, Formula Conversion every 26 months. The most recent releases landed on September 26, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | iPeriodic for iPhone | Formula Conversion |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 8 days** | Every 26 months |
| Size | 16 MB | 2 MB |
| Requires iOS | **6.1** | 14.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Thitipong Wongsatho](https://appshunter.io/developer/683911170) | [Janek Soomets](https://appshunter.io/developer/1315295062) |

## What reviewers say

### iPeriodic for iPhone

[App page](https://appshunter.io/ios/app/iperiodic-for-iphone/id963558647)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads ($0.99) | $0.99 | one-time |


### Formula Conversion

[App page](https://appshunter.io/ios/app/formula-conversion/id1586539965)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Upgrade Formula Conversion | $3.99 | one-time |


## Frequently asked questions

### Is iPeriodic for iPhone free?

iPeriodic for iPhone is free to download, with in-app purchases available.

### Is Formula Conversion free?

Formula Conversion is free to download, with in-app purchases available.

### Do iPeriodic for iPhone or Formula Conversion have ads?

Neither iPeriodic for iPhone nor Formula Conversion shows ads.

### Which is updated more often, iPeriodic for iPhone or Formula Conversion?

iPeriodic for iPhone ships an update every 8 days, and Formula Conversion every 26 months. Most recently, iPeriodic for iPhone was updated on September 26, 2026 and Formula Conversion on September 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*